138 research outputs found
Effect of temperature during on in vitro multiplication of Limonium sinuatum
[SPA] La temperatura es uno de los factores más importantes en la fase de multiplicación en el cultivo in vitro de Limonium sinuatum. En términos generales este factor afecta, especialmente, a la velocidad de crecimiento y a la tasa de multiplicación. Este trabajo muestra los resultados del comportamiento de un ensayo de cuatro variedades de limonio de distintos colores, SN9001, SN8946, SN9000, SN9013, cultivadas en medio Murashige y Skoog (MS) suplementado con N6-benziladenina (BA) a temperaturas de 4 °C, 12 °C y 22 °C. Entre las determinaciones realizadas, se tomaron medidas del crecimiento de las plantas y de la tasa de propagación. También se midió la producción y la longitud del tallo durante la fase de cultivo en invernadero. Los resultados obtenidos muestran que el efecto de la temperatura depende de la variedad estudiada, de manera que para cada una de ellas es posible subcultivar a una determinada temperatura para aumentar el periodo de subcultivo, bajando los requerimientos de mano de obra, y sin perjudicar a la producción ni a los valores requeridos en los parámetros de calidad estudiados.
[ENG] Temperature is one of the most important factors in the multiplication phase in the tissue culture of Limonium sinuatum. This factor has an effect on the speed of growth and multiplication rate. This paper shows the performance results of a trial of four varieties of statice of different colours, SN9001, SN8946, SN9000, SN9013, grown in Murashige and Skoog basal medium (MS) supplemented with N6-benzilademina (BA) at temperatures of 4 °C , 12 °C and 22 °C. Among the determinations, measurements of plant growth and propagation rate were taken. Production and stem length during the greenhouse cultivation was also measured. The results obtained show that the effects produced by temperature depend on the studied variety, in such a way that for each one of them it is possible to subcultivate it at a specific temperature so that it increases the subcultivation period, lowering the labor requests, and without harming either to the production or to the values needed in the parameters of quality.Este trabajo está siendo apoyado y financiado por la empresa Barberet & Blanc, S.A. Algunos de los ensayos han sido llevados a cabo en las instalaciones del Instituto de Biotecnología Vegetal de la UPCT
Tumor-derived pericytes driven by egfr mutations govern the vascular and immune microenvironment of gliomas
The extraordinary plasticity of glioma cells allows them to contribute to different cellular compartments in tumor vessels, reinforcing the vascular architecture. It was recently revealed that targeting glioma-derived pericytes, which represent a big percentage of the mural cell population in aggressive tumors, increases the permeability of the vessels and improves the efficiency of chemotherapy. However, the molecular determinants of this transdifferentiation process have not been elucidated. Here we show that mutations in EGFR stimulate the capacity of glioma cells to function as pericytes in a BMX- (bone marrow and X-linked) and SOX9-dependent manner. Subsequent activation of platelet-derived growth factor receptor beta in the vessel walls of EGFR-mutant gliomas stabilized the vasculature and facilitated the recruitment of immune cells. These changes in the tumor microenvironment conferred a growth advantage to the tumors but also rendered them sensitive to pericyte-targeting molecules such as ibrutinib or sunitinib. In the absence of EGFR mutations, high-grade gliomas were enriched in blood vessels, but showed a highly disrupted blood–brain barrier due to the decreased BMX/SOX9 activation and pericyte coverage, which led to poor oxygenation, necrosis, and hypoxia. Overall, these findings identify EGFR mutations as key regulators of the glioma-to-pericyte transdifferentiation, highlighting the intricate relationship between the tumor cells and their vascular and immune milieu. Our results lay the foundations for a vascular-dependent stratification of gliomas and suggest different therapeutic vulnerabilities determined by the genetic status of EGFR.This work was supported by FONDECYT grant (1140697 to V. Palma), CONICYT Fellowship (to B.S. Casas), by Ministerio de Economía y Competitividad and FEDER funds (PI13/01258 to A. Hernandez-Laín; PI17/01621 to J.M. Sepulveda-S anchez; and PI16/01580 and DTS18/00181 to A. Matheu), by Young Employment Initiative
(Comunidad de Madrid) to M. Garranzo-Asensio, by “Asociacion Espanola contra ~ el Cancer” (AECC) grants (INVES192GARG to R. Gargini; GCTRA16015SEDA to J.M. Sepulveda-S anchez); and by Ministerio de Ciencia, Innovacion y Universidades and FEDER funds (RTI2018-093596 to P. Sanchez-Gomez).Peer reviewe
Electronic properties and Fermi surface of Ag(111) films deposited onto H-passivated Si(111)-(1x1) surfaces
Silver films were deposited at room temperature onto H-passivated Si(111)
surfaces. Their electronic properties have been analyzed by angle-resolved
photoelectron spectroscopy. Submonolayer films were semiconducting and the
onset of metallization was found at a Ag coverage of 0.6 monolayers. Two
surface states were observed at -point in the metallic films,
with binding energies of 0.1 and 0.35 eV. By measurements of photoelectron
angular distribution at the Fermi level in these films, a cross-sectional cut
of the Fermi surface was obtained. The Fermi vector determined along different
symmetry directions and the photoelectron lifetime of states at the Fermi level
are quite close to those expected for Ag single crystal. In spite of this
concordance, the Fermi surface reflects a sixfold symmetry rather than the
threefold symmetry of Ag single crystal. This behavior was attributed to the
fact that these Ag films are composed by two domains rotated 60.Comment: 9 pages, 8 figures, submitted to Physical Review
Quantum-well states in ultrathin Ag(111) films deposited onto H-passivated Si(111)-(1x1) surfaces
Ag(111) films were deposited at room temperature onto H-passivated
Si(111)-(1x1) substrates, and subsequently annealed at 300 C. An abrupt
non-reactive Ag/Si interface is formed, and very uniform non-strained Ag(111)
films of 6-12 monolayers have been grown. Angle resolved photoemission
spectroscopy has been used to study the valence band electronic properties of
these films. Well-defined Ag sp quantum-well states (QWS) have been observed at
discrete energies between 0.5-2eV below the Fermi level, and their dispersions
have been measured along the GammaK, GammaMM'and GammaL symmetry directions.
QWS show a parabolic bidimensional dispersion, with in-plane effective mass of
0.38-0.50mo, along the GammaK and GammaMM' directions, whereas no dispersion
has been found along the GammaL direction, indicating the low-dimensional
electronic character of these states. The binding energy dependence of the QWS
as a function of Ag film thickness has been analyzed in the framework of the
phase accumulation model. According to this model, a reflectivity of 70% has
been estimated for the Ag-sp states at the Ag/H/Si(111)-(1x1) interface.Comment: 6 pages, 6 figures, submitted to Phys. Rev.
Magnetobiochronology of lower Pliocene marine sediments from the lower Guadalquivir Basin: insights into the tectonic evolution of the Strait of Gibraltar area
The Gibraltar Arc is a complex tectonic region, and several competing models have been proposed to explain its evolution. We studied the sedimentary fill of the Guadalquivir Basin to identify tectonic processes that were occurring when the reopening of the Strait of Gibraltar led to the reestablishment of Mediterranean outflow. We present a chronostratigraphic framework for the Lower Pliocene sediments from the lower Guadalquivir Basin (SW Spain). The updated chronology is based on magnetobiostratigraphic data from several boreholes. Our results show that the studied interval in the La Matilla core is in the early Pliocene section, providing better constraints on the sedimentary evolution of the basin during that period. Migrating depositional facies led to a younger onset of sandy deposition basinward. At the northwestern passive margin, a 0.7 m.y. period of sedimentary bypass related to a sharp decrease in sedimentation rates and lower sea levels resulted from the tectonic uplift of the forebulge. In contrast, high sedimentation rates with continuous deep-marine sedimentation are recorded at the basin center due to continuous tectonic subsidence and west-southwestward progradation of axial depositional systems. The marginal forebulge uplift, continuous tectonic basinal subsidence, and southward progradation of clinoforms in the early Pliocene can be explained by the pull of a lithospheric slab beneath the Gibraltar Arc as the Strait of Gibraltar opened. These findings are, to our knowledge, the first reported sedimentary expression of slab pull beneath the Betics related to the opening of the Strait of Gibraltar after the Messinian salinity crisis
DEVELOPING TECHNICAL ENGLISH SKILLS FOR CIVIL ENGINEERING STUDENTS
Traditionally, Spanish schools of civil engineering provide their students a class on “Technical English” in order to develop their language skills. However, this class does not cover all the skills that the student would need in the labor market and mainly focuses in the reading and writing skills, and in a lower degree in the speaking and listening ones. This paper proposes a series of innovative and informal training activities, such as cine-forum on technical civil engineering topics and role playing on real professional situations, that allow Spanish civil engineering students to develop English skills, that can rarely be worked in the classroom (i.e. speaking, negotiating and conversing), which encourage debate, participation, and foster their self-confidence to speak about technical-English topics in public. Although the students’ level of English is much lower than expected, they all agree on the importance of technical English for their future career. The results also show the students’ lack in skills that are difficult to train in regular classes (speaking and talking). Consequently, this situation would require to provide complementary activities like the ones suggested in this project in order to develop these skills and increase the students’ demand for engineering classes taught in English
Two-domains bulklike Fermi surface of Ag films deposited onto Si(111)-(7x7)
Thick metallic silver films have been deposited onto Si(111)-(7x7) substrates
at room temperature. Their electronic properties have been studied by using
angle resolved photoelectron spectroscopy (ARPES). In addition to the
electronic band dispersion along the high-symmetry directions, the Fermi
surface topology of the grown films has been investigated. Using ARPES, the
spectral weight distribution at the Fermi level throughout large portions of
the reciprocal space has been determined at particular perpendicular
electron-momentum values. Systematically, the contours of the Fermi surface of
these films reflected a sixfold symmetry instead of the threefold symmetry of
Ag single crystal. This loss of symmetry has been attributed to the fact that
these films appear to be composed by two sets of domains rotated 60 from
each other. Extra, photoemission features at the Fermi level were also
detected, which have been attributed to the presence of surface states and
\textit{sp}-quantum states. The dimensionality of the Fermi surface of these
films has been analyzed studying the dependence of the Fermi surface contours
with the incident photon energy. The behavior of these contours measured at
particular points along the Ag L high-symmetry direction puts forward
the three-dimensional character of the electronic structure of the films
investigated.Comment: 10 pages, 12 figures, submitted to Physical Review
Small-scale solar magnetic fields
As we resolve ever smaller structures in the solar atmosphere, it has become
clear that magnetism is an important component of those small structures.
Small-scale magnetism holds the key to many poorly understood facets of solar
magnetism on all scales, such as the existence of a local dynamo, chromospheric
heating, and flux emergence, to name a few. Here, we review our knowledge of
small-scale photospheric fields, with particular emphasis on quiet-sun field,
and discuss the implications of several results obtained recently using new
instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure
Probing the Nuclear and Circumnuclear Activity of NGC1365 in the Infrared
We present new far-infrared (70-500micron) Herschel PACS and SPIRE imaging
observations as well as new mid-IR Gemini/T-ReCS imaging (8.7 and 18.3micron)
and spectroscopy of the inner Lindblad resonance (ILR) region (R<2.5kpc) of the
spiral galaxy NGC1365. We complemented these observations with archival Spitzer
imaging and spectral mapping observations. The ILR region of NGC1365 contains a
Seyfert 1.5 nucleus and a ring of star formation with an approximate diameter
of 2kpc. The strong star formation activity in the ring is resolved by the
Herschel/PACS imaging data, as well as by the Spitzer 24micron continuum
emission, [NeII]12.81micron line emission, and 6.2 and 11.3micron PAH emission.
The AGN is the brightest source in the central regions up to lambda~24micron,
but it becomes increasingly fainter in the far-infrared when compared to the
emission originating in the infrared clusters (or groups of them) located in
the ring. We modeled the AGN unresolved infrared emission with the CLUMPY torus
models and estimated that the AGN contributes only to a small fraction (~5%) of
the infrared emission produced in the inner ~5kpc. We fitted the non-AGN
24-500micron spectral energy distribution of the ILR region and found that the
dust temperatures and mass are similar to those of other nuclear and
circumnuclear starburst regions. Finally we showed that within the ILR region
of NGC1365 most of the on-going star formation activity is taking place in
dusty regions as probed by the 24micron emission.Comment: Accepted for publication in MNRA
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